package com.atguigu.aspect;

import com.atguigu.annotations.MyRedisCache;
import jakarta.annotation.Resource;
import lombok.extern.slf4j.Slf4j;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.MethodSignature;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.stereotype.Component;

import java.lang.reflect.Method;
import java.lang.reflect.Parameter;

@Component
@Aspect
@Slf4j
public class MyRedisCacheAspect {
    @Resource
    private RedisTemplate redisTemplate;
    @Resource
    private RabbitTemplate rabbitTemplate;

    //配置织入点
    @Pointcut("@annotation(com.atguigu.annotations.MyRedisCache)")
    public void cachePointCut(){}

    @Around("cachePointCut()")
    public Object doCache(ProceedingJoinPoint joinPoint){
        Object result = null;
        try {
            //1.获得重载后的方法名
            MethodSignature signature = (MethodSignature) joinPoint.getSignature();
            Method method = signature.getMethod();

            //2.确定方法名后获得该方法上面配置的注解标签MyRedisCache
            MyRedisCache myRedisCacheAnnotation = method.getAnnotation(MyRedisCache.class);

            //3.拿到了MyRedisCache这个注解标签，获得该注解上面配置的参数进行封装调用
            String keyPrefix = myRedisCacheAnnotation.keyPrefix();
            String matchValueSpringEl = myRedisCacheAnnotation.matchValue();

            //4. SpringEL 解析器
            ExpressionParser parser =  new SpelExpressionParser();
            Expression expression = parser.parseExpression(matchValueSpringEl);
            EvaluationContext context = new StandardEvaluationContext();

            //5.使用反射获得方法里面的形参信息
            Object[] args = joinPoint.getArgs();
            Parameter[] parameterNames = method.getParameters();
            for (int i = 0; i < parameterNames.length; i++) {
                System.out.println("获取方法里参数名和值" + parameterNames[i].getName() + "\t" + args[i].toString());
                context.setVariable(parameterNames[i].getName(),args[i].toString());
            }


            //6.通过上述，拼接redis的最终key形式
            String key = keyPrefix + ":" + expression.getValue(context).toString();
            System.out.println("----拼接redis的最终key形式" + key);


            //7.先去redis里面查看有无
            result = redisTemplate.opsForValue().get(key);
            if(result != null){
                System.out.println("-----------redis里面有，直接返回不打扰mysql" + result);
                return result;
            }

            //8.redis里面没有去mysql查找
            //----aop部分， 采取getUserById方法干活
            //主业务逻辑查询mysql放行到userMapper.selectById(id)

            result = joinPoint.proceed();



            //9.mysql步骤结束，还需要缓存补偿到redis
            if(result != null){
                System.out.println("-----------redis无，需要把结果再存入redis：缓存补偿" + result);
                redisTemplate.opsForValue().set(key,result);
            }
        } catch (Throwable e) {
            e.printStackTrace();
        }
        return result;
    }

}
